A technology for the radiometric correction of high spatial resolution imagery (aerial or UAV). The imagery is calibrated to approximate surface reflectance by fusing with concurrent and collocated satellite imagery. The technique allows the production of seamless mosaics corrected for coarse scale atmospheric and bidirectional reflectance distribution function (BRDF) effects and does not, like many existing methods, require the manual acquisition (or provision) of ground reflectance references.
This technology could find applications in various industries requiring:
Examples of potential target industries are forestry, conservation, and climate change.
The use of high spatial resolution aerial and or UAV imagery is limited by radiometric variations cased by atmospheric and BRDF effects. The variations creates discontinuities and gradients between and within images, and inhibit their use for quantitative analysis.
This technology corrects the radiometric variations without the need for manual field relectance measurments, the placements of targets of known reflectance, or detailed knowledge of atmoshperic conditions. The technique is relatively computationally efficient and can be applied to large moasaics of imagery consisting of thousands of image.
A proof of concept was developed and tested for high resolution (50cm) multi-spectral aerial imagery by calibrating with (500m) MODIS satellite data. The result was published as a peer-reviewed scientific article in the International Journal of Remote Sensing. The technology was implemented in C++ programming language. An application programming interface (API) needs to be developed to make the technology more accessible and easier to use. Further testing and development is required to extend its use, and evaluate on UAV imagery and other satellite data.
Patents protecting the technology were filed in the following territories:
Prof Adriaan van Niekerk
Dr Dugal Harris